Garrett F124 / F125 / TFE1042
The Honeywell/ITEC F124 is a low-bypass turbofan engine derived from the civilian Honeywell TFE731. The F125 is an afterburning version of the engine. The engine began development in the late 1970s for the Republic of China (Taiwan) Air Force AIDC F-CK Indigenous Defence Fighter (IDF), and it first ran in 1979. The F124/F125 engine has since been proposed for use on other aircraft, such as the T-45 Goshawk and the SEPECAT Jaguar, and powers the Aero L-159 Alca and the Alenia Aermacchi M-346.
The F124 engine is fundamentally a low bypass, two spool engine (meaning that there are two rotational shafts, a high pressure shaft and a low pressure shaft. The fan/low pressure compressor section is made of three stages with titanium blades. The first stage has 30 un-shrouded blades, and the overall pressure ratio for the three stage fan section is 2.5:1. Some of the air is bypassed (Bypass ratio of 0.472:1), and the rest is fed to the high pressure compressor section.
By 2004 at total of 460 F124 had been built with an estimated unit cost in 2006 of USD$2.5 million.
In 1978, Garrett announced joint research on the TFE1042 afterburner with Swedish company Volvo Flygmotor AB in order to provide an engine for the AIDC F-CK Indigenous Defence Fighter (IDF) being developed for the Republic of China (Taiwan) Air Force (ROCAF). The TFE731 Model 1042 was touted as a low bypass ratio "military derivative of the proven commercial TFE731 engine" and "provides efficient, reliable, cost effective propulsion for the next generation of light strike and advanced trainer aircraft", with thrust of 4260 lbf (18.9 kN) dry and 6790 lbf (30.2 kN) with afterburner. After initial negotiation, the investment was going to be divided between Garrett, Volvo, AIDC, and Italian company Piaggio. The development would consist of the non-afterburning TFE1042-6 for light attack aircraft/advanced trainer, and TFE1042-7 for the AMX or F-5 upgrade. Garrett would be responsible for the core engine, and Volvo would be responsible for the fan section and the afterburner. The engine first ran for 3 hours at a Volvo test facility in 1979.
AIDC also suggested upgrading TFE1042-7 to 8000 lbf (31 to 36 kN) thrust as twin engine solution, in order to compete with General Electric F404 for applications such as the JAS 39 Gripen. However, the Gripen project decided to continue with a single engine F404 variant, built by Volvo, and Volvo left the project to at that point to focus on the Gripen work. Piaggio asked to participate at a later date due to financial reasons and left the program as well. Thus only Garrett and AIDC invested in the new International Turbine Engine Corporation(ITEC), with the contract signed in 1982.
In 1988, ITEC decided to invest in the 12,000 lb TFE1088-12, which was re-designated as TFE1042-70A (for political reason as well). Preliminary study had shown that IDF could supercruise with the new engine. At the same time, GE decided to enter the market with J101/SF, a smaller version of F404. However after the IDF order was cut in half due to budget concerns, the TFE1088-12 engine upgrade plan ended as well. The F-CK IDF first flew in 1989, and aircraft were delivered through 1999.
In the early 1990s, the United States Navy considered the re-engining their fleet of T-45 Goshawk trainer aircraft with the F124. In 1994, after flight testing a T-45 with the engine, the USN elected not to do that.
The possibility of a F124-powered T-45 arose again in 1996 when McDonnell Douglas offered an F124-engined T-45 to the Royal Australian Air Force as a competitor for their trainer requirement. BAe wanted to offer the F124 as an option on their entry for the RAAF trainer requirement, the BAE Hawk (which the T-45 is based on), but ITEC refused to give BAe permission to offer it. ITEC's decision turned out to be a mistake, as the RAAF select the Hawk as their trainer. However, after the selection of the aircraft, the RAAF decided to have a separate competition between the F124 and the Rolls-Royce Turbomeca Adour (which was BAe's selection) to power the new trainers. In 1997 the RAAF elected to used the Adour engine, effectively ending the F124's chances of being used on Hawk or T-45 aircraft.
In 1994, the F124 engine was selected to power the Czech Aero L-159 Alca light combat aircraft. The combination first flew in 1997.
In 2000, Alenia Aermacchi announced that their new M-346 trainer/light attack aircraft would be powered by the F124 engine, choosing it over its common rival, the Adour. In 2009, the United Arab Emirates announced that their M-346 trainers would be powered by the F124-GA-200.
The F124 engine powered the Boeing X-45A unmanned combat air vehicle demonstrator in the early 2000s.
The afterburning F125 engine is being considered, as of 2009, by the Indian Air Force as a replacement for the Rolls-Royce Turbomeca Adour engines in their SEPECAT Jaguar aircraft. The new engine would be both lighter and more powerful. It was successfully demonstrated in 2007.